Help me beat hard AI

Hey,

Me and my friend got the game a couple weeks ago and started playing and realizing this game is a lot more difficult than we remembered from many years ago. In the beginning we couldn't even beat the moderate AI, but after a couple games we got the hang of it and can 100% beat it no problem. So we decided to try hard AI but man thats such a huge jump for us :(

I can hold their initial wave with archers and skirms etc but later in castle age the score differencial really separates and I'm at best 400-500 points below the AIs. I've been watching youtube videos and learning counters and build orders but still have lots of trouble. One of the games I went for fast castle 20 knights and got a pretty good raid, killed like 15-20 villagers and then I saw the horror of like 10 pikemen and 30 knights I fell back to my castle and start making pikes myself but it just snowballs and eventually the AI just murders everything I have.